The scene of the crime… Police outside the Brink’s-Mat warehouse at Heathrow Airport (Picture: Daily Mail)

‘Thanks ever so much for your help. Have a very nice Christmas.’

It may seem like a strange thing for an armed thief to say to a group of bound security guards, but the Brink’s-Mat robbery was no ordinary heist. It changed the lives – for better or worse – of the robbers, it led to a trail of bloodshed and it altered Britain’s criminal landscape. And it all took less than two hours.

Shortly after 6.40am on November 26, 1983, six armed men in balaclavas – one in a yellow balaclava topped off with a Trilby hat, bizarrely – entered a warehouse at Heathrow Airport. The property belonged to security company Brink’s-Mat and the robbers were there because they knew there was £3m in cash in the vault. They knew because their inside man, security guard Anthony Black, had told them. He even opened the door of the warehouse to let them in, but not until after he arrived ten minutes late for work that day, having slept in.

Led by Black’s brother-in-law, Brian Robinson, and Trilby-clad Micky McAvoy, the gang rounded up the guards, tied them up and poured petrol over them, threatening to light them with a match if they didn’t comply. Thanks to Black, they were able to identify the two most senior guards who, between them, held the keys and combination numbers for the vault where three safes were located.

When the robbers gained access, they were greeted with a sight usually reserved for heist movies. The cash was no longer the focus of their operation – the warehouse was storing more than three tonnes of gold bullion. Packed into more than 70 cardboard boxes were almost 7,000 gold bars. Someone had to fetch the van.

‘It was one of those apocryphal stories in a sense that every villain dreams of. He pulls off a job and finds there’s 20 times more there than he thought there would be.’

Weighed down by a hunk of gold, the van idled its way out of Heathrow after one of the robbers wished the security guards a merry Christmas. Most of the gold would never be found. Some of the robbers weren’t so fortunate.

‘From the moment they found the gold, put it in that van which had scraped its way out of the Brink’s-Mat warehouse, their problems began,’ said Clarkson. ‘In the last 30 years, it hasn’t got any better for them.’

It didn’t take the police long to connect Black to the heist and he soon implicated Robinson and McAvoy (who punched Black when he went to identify him in a police line-up). The pair hadn’t exactly laid low after the robbery, spending cash on property in Kent. It was rumoured that McAvoy had bought two Rottweiler dogs to protect his new home and named them ‘Brinks’ and ‘Mat’. The pair were later sentenced to 25 years in prison. Another criminal, Tony White, was found not guilty. He was later jailed for his part in a drug smuggling ring. Black was sentenced to six years in prison.

Stealing the gold had been relatively easy. The bigger challenge was selling it. The gold ingots had to be melted down to get rid of their traceable serial numbers, but selling pure gold was not an option, so it was mixed with copper and other metals to disguise it.

The robbers turned to crime boss Kenneth Noye, who, along with another criminal, Brian Reader, handled the gold. It was regularly taken to a smelting company near Bristol where it was mixed with copper and brass to look like scrap gold. About £13m worth of gold was disposed of in this way. The movement of cash through a local bank soon aroused the suspicion of the Bank of England.

In a tragic twist, Detective Constable John Fordham was stabbed to death by Noye when he was discovered during a surveillance operation in the garden of his Kent’s home. At a trial in December 1985, Noye was cleared of murder after pleading self-defence. Noye stabbed DC Fordham 11 times. However, he was back in court a few months later after police found 11 gold bars worth £100,000 on his premises. He was found guilty of handling the Brink’s-Mat gold and was sentenced to 14 years in prison. He served seven years before he was released in 1994. Two years later, Noye murdered motorist Stephen Cameron, 21, after a road rage incident on the M25. He was extradited after fleeing to Spain and is currently serving a life sentence in prison.

Only two of the gang of robbers that entered the warehouse were ever convicted for the crime, but there were greater repercussions outside the prison walls. It is estimated that more than 20 people with some kind of connection to the robbery have been killed, as Britain’s criminal underworld turned on itself.

They include Brian Perry, sentenced to nine years in prison in 1992 for his part in handling the gold, who was shot dead in south-east London in 2001, and George Francis, who was executed two years later.

Solly Nahome, a jeweller in London’s Hatton Garden who had helped dispose of some of the gold, was murdered in 1998 outside his home in Finchley, north London. The carnage also stretched abroad – and to someone connected to an even more infamous heist – when Great Train Robber Charlie Wilson was shot dead – along with his dog – on his doorstep in Marbella, Spain, by a young British hood who left the scene on a yellow bicycle. Wilson had been tasked to launder some of the Brink’s-Mat proceeds.

‘People did make a lot of money out of that robbery but the problems, death and destruction which have come since are probably not worth it,’ said Clarkson. ‘The tentacles of that crime are enormous. They spread across many deaths and many continents and there are still reverberations until this day. The early intake of ecstasy into Britain came directly through Brink’s-Mat’s money that was made from the job and then ploughed back into ecstasy, which was a brand new drug. It marked a crossover from robbery to drugs.’

Clarkson said his sources tell him there is still at least £10m worth of gold out there somewhere, buried in farmyards and scrap metal yards. With so many deaths already connected to it, perhaps it’s just not worth finding.

‘It belongs to the era in which it was committed,’ said Clarkson of the heist. ‘It’s something that you’ll probably never see again.’